Background and Relevant Art
Computer systems and related technology affect many aspects of society. Indeed, the computer system's ability to process information has transformed the way we live and work. Computer systems now commonly perform various tasks (e.g., word processing, scheduling, and database management) that prior to the advent of the computer system were performed manually. Typically, to perform these various tasks, a computer system includes a number of corresponding applications. For example, to perform word processing a computer system can include a word processing application, to manipulate spreadsheets a computer system can include a spreadsheet application, etc.
In a standalone computing environment, it is often useful to be able to move objects between applications that perform different tasks at a computer system. For example, it may be useful to move a portion of text generated in word processing application into a presentation program as the descriptive text for a picture or drawing. To enable movement of objects between applications, some computer systems include a portion of memory (e.g., a clipboard) that can be interfaced in a common manner by applications at the computer system. Thus, one application can interface with the portion of memory to store an object and then another application can interface with the portion of memory to retrieve the object. Thus, applications (even those that cannot compatibly exchange objects directly) can exchange objects through the portion memory.
Many standalone computing environments also include the more convenient ability to use input devices in combination with visual cues to directly transfer objects between compatible applications. One common mechanism for direct transfer between applications is “drag and drop”. To facilitate drag and drop, a user identifies an object in one application (e.g., a portion of text, a picture, or a spreadsheet cell). For example, the user can highlight a portion of text with a mouse. A visual cue, for example, back lighting, can be used to indicate to the user that the text is selected.
The user manipulates input devices to select the identified object. For example, the user manipulates a mouse to move a cursor over the identified text and then can depress a left mouse button. The user then further manipulates input devices to move the object to another application. For example, while keeping the left mouse button depressed, the user can manipulate the mouse to move (drag) the cursor over the top of the other application. Once on top of the other application, the user can release the left mouse button. The act of releasing the mouse button causes the object to be transferred to (or dropped into) the other application.
In other environments, computer systems are coupled to one another and to other electronic devices to form both wired and wireless computer networks over which the computer systems and other electronic devices can transfer electronic data. As a result, many tasks performed at a computer system (e.g., voice communication, accessing electronic mail, controlling home electronics, Web browsing, and printing documents) include the communication (e.g., the exchange of electronic messages) between a number of computer systems and/or other electronic devices via wired and/or wireless computer networks.
In a networked environment, it is also often useful to be able to move objects between applications that perform different tasks, wherein some applications are run locally and other applications are run remotely, for example, at a terminal server. A terminal server is a computer system that maintains applications that can be remotely executed by client computer systems. Input is entered at a client computer system and transferred over a network (e.g., using protocols based on the ITU T.120 family of protocols, such as, for example, Remote Desktop Protocol (“RDP”)) to an application at the terminal server. The application processes the input as if the input was entered at the terminal server. The application generates output in response to the received input and the output is transferred over the network (e.g., also T.120 based protocols) to the client computer system. The client computer system presents the output data. Thus, input is received and output presented at the client computer system, while processing actually occurs at the terminal server.
To enable movement of objects between local and remote applications, some networked computer systems include clipboard functionality similar that used in a standalone environment. A portion of memory (or clipboard) is allocated and can be interfaced in a common manner by applications at the computer system. Thus, a local application can interface with the portion of memory to store an object and then a remote application can interface with the portion of memory to retrieve the object or vice versa. Thus, applications (even those running at different computer systems) can exchange objects through the portion memory.
However, many networked computer systems lack the more convenient ability to drag and drop objects between local and remote applications and vice versa. That is, client and server terminal server components are typically not configured to transfer drag and drop objects over a terminal server session and to interact with a drop source or drop target to facilitate a drag and drop transfer. For example, a server component typically has no way to determine if the movement of a mouse cursor outside of a remote desktop window (at a client system) is associated with a drop and drop operation or if a user is moving the mouse for other reasons.